The Biggest Breakthrough In Propulsion Since The Jet Engine

Aircraft projects are not really my thing, so feel free to give me a kick if I am behind the times here but..this looks like it could be big.

Reaction Engines can announce the biggest breakthrough in aerospace propulsion technology since the invention of the jet engine. Critical tests
have been successfully completed on the key technology for SABRE, an engine which will enable aircraft to reach the opposite side of the world in
under 4 hours, or to fly directly into orbit and return in a single stage, taking off and landing on a runway.

It's basically a hydrogen engine. This reminds me of the work NASA did on hydrogen efficiency with lean fuel burn tests, (something that gets
misquoted by HHO proponents all the time). Although, this also uses insane compression:

In the past, attempts to design single stage to orbit propulsion systems have been unsuccessful largely due to the weight of an on-board oxidiser such
as liquid oxygen, needed by conventional rocket engines. One possible solution to reduce the quantity of on-board oxidizer required is by using oxygen
already present in the atmosphere in the combustion process just like an ordinary jet engine.

While this sounds simple, the problem is that in air-breathing mode, the air must be compressed to around 140 atmospheres before
injection into the combustion chambers which raises its temperature so high that it would melt any known material. SABRE avoids this by
first cooling the air using a Pre-cooler heat exchanger until it is almost a liquid. Then a relatively conventional turbo compressor using jet engine
technology can be used to compress the air to the required pressure.

Gasoline engines take in a mixture of air and gasoline and compress it to not more than 12.8 bar (1.28 MPa), then use a spark plug to ignite the
mixture when it is compressed by the piston head in each cylinder.

I seriously doubt this will make it into commercial passenger jets any time soon, the designs that are needed for the speeds produced by this tech
would be pretty tough to apply. Think SR71.

Although, this seems to completely blow every private space plane program way out of the water. Richard Branson is is likely salivating over getting
his hands on this engine. They will have immediate sales if they can prove reliability and efficacy.

I have been following the Skylon development for some time, and indeed it is big. If successfull, Skylon will revolutionise both air and space travel.
And so far it seems like they are on the right track.

EDIT: If you are interested in details, there is a 100+ page thread about Skylon on nasaspaceflight.com, with contributions from Skylon engineers
themselves:

They said this would save lifting 250 tons of cryogenic oxidizer, but how much liquid Hydrogen will they need to precool that much air down below -183
where oxygen changes mass? Sounded like they were building a high speed oxygen distillery. They must be raising the pressure much higher than just 5
or 10 atmospheres so that the liquefaction takes place at a relatively high temperature.

While fascinating and promising, I cant help but think this exciting discovery will go the same way as its predecessor, HOTOL. Unless the Americans
buy it of course.

Always a possibility, however this one has gotten off of the drawing board, passed several ESA tests and has received some government moneys. So it
has gotten further than HOTOL did. If they can get past the next phase i wouldn't be at all surprised to see a US company buy them out tbh.

BBC seems to have quite a few updates on this project every now and again as well, latest is here.

Originally posted by andy06shake
This looks promising! But what happens when the heat condenser fails midflight and the engine becomes superheated will it explode? Hope the have there
tech tolerances down to a tee.

edit on 30-11-2012 by andy06shake because: (no reason given)

Rocketry FAQ (applies to all models since 1943)

Q: what happens when (one of hundreds of critical parts) fails (during fueling|at ignition|during launch|midflight|course-correction|re-entry) and the
(engine/fuel/oxidizer/guidance/turbopump) does (abnormal behavior X,Y,Z,A,B,C,D,E,F,G, etc)

I thought the point of this engine and its precooling is that it is NOT a rocket at that stage?

Rather the cooling reduces the temperature of the incoming air to a point wher eit can be usefully used.

Or have I misunderstood?

the fuel is crygenically cooled hydrogen - and it is a helium heat intercooler that cools the incoming air charge, and that heat is used to power
parts of the engine and also heat the hydrogen prior to combustion. In effect the cycle of the helium is the same as a jet engine - but instead of
combustion it is getting its energy to do work from the air.

Originally posted by andy06shake
This looks promising! But what happens when the heat condenser fails midflight and the engine becomes superheated will it explode? Hope the have there
tech tolerances down to a tee.

edit on 30-11-2012 by andy06shake because: (no reason given)

The same thing that happened when Wilbur asked Orville, what happens if this belt pulley comes off this engine?

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